In computing, an interrupt is a message sent by a device requesting the attention of, for example, a processor. Interrupts are often used in implementing multitasking. The interrupt is designed to get the processor to pause what it is currently being processed, for example by saving its state of execution via a context switch, so as to begin processing the request associated with the interrupt. Context switching can be relatively expensive in terms of processor time and resources.
One type of interrupt, known as a message-signaled interrupt, uses different types of interrupts for different situations. Each interrupt type includes information about the interrupting device and the required task. As the number of devices and interrupt types increase, so does the demand on the processor. Eventually, there is a point at which the number of interrupts will begin to overwhelm the processor, thereby undermining any performance benefit of using interrupts to do multitasking.